mmc: Add multi-block read support to the generic mmc driver
This patch adds multi-block read support for the generic MMC
driver. Large reads are broken into chunks of 65535 blocks to
ensure that the code works with controllers having a 16 bit block counter.
This patch results in a significant performance improvement.
Time to read a 45 MB file went from 36 seconds to 9 seconds on Overo
Signed-off-by: Steve Sakoman <steve.sakoman@linaro.org>
Tested-by: Steve Sakoman <steve.sakoman@linaro.org>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>
diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
index 00fe867..6805b33 100644
--- a/drivers/mmc/mmc.c
+++ b/drivers/mmc/mmc.c
@@ -154,110 +154,78 @@
return blkcnt;
}
-int mmc_read_block(struct mmc *mmc, void *dst, uint blocknum)
+int mmc_read_blocks(struct mmc *mmc, void *dst, ulong start, lbaint_t blkcnt)
{
struct mmc_cmd cmd;
struct mmc_data data;
- cmd.cmdidx = MMC_CMD_READ_SINGLE_BLOCK;
+ if (blkcnt > 1)
+ cmd.cmdidx = MMC_CMD_READ_MULTIPLE_BLOCK;
+ else
+ cmd.cmdidx = MMC_CMD_READ_SINGLE_BLOCK;
if (mmc->high_capacity)
- cmd.cmdarg = blocknum;
+ cmd.cmdarg = start;
else
- cmd.cmdarg = blocknum * mmc->read_bl_len;
+ cmd.cmdarg = start * mmc->read_bl_len;
cmd.resp_type = MMC_RSP_R1;
cmd.flags = 0;
data.dest = dst;
- data.blocks = 1;
+ data.blocks = blkcnt;
data.blocksize = mmc->read_bl_len;
data.flags = MMC_DATA_READ;
- return mmc_send_cmd(mmc, &cmd, &data);
-}
-
-int mmc_read(struct mmc *mmc, u64 src, uchar *dst, int size)
-{
- char *buffer;
- int i;
- int blklen = mmc->read_bl_len;
- int startblock = lldiv(src, mmc->read_bl_len);
- int endblock = lldiv(src + size - 1, mmc->read_bl_len);
- int err = 0;
-
- /* Make a buffer big enough to hold all the blocks we might read */
- buffer = malloc(blklen);
-
- if (!buffer) {
- printf("Could not allocate buffer for MMC read!\n");
- return -1;
- }
-
- /* We always do full block reads from the card */
- err = mmc_set_blocklen(mmc, mmc->read_bl_len);
-
- if (err)
- goto free_buffer;
-
- for (i = startblock; i <= endblock; i++) {
- int segment_size;
- int offset;
-
- err = mmc_read_block(mmc, buffer, i);
-
- if (err)
- goto free_buffer;
-
- /*
- * The first block may not be aligned, so we
- * copy from the desired point in the block
- */
- offset = (src & (blklen - 1));
- segment_size = MIN(blklen - offset, size);
-
- memcpy(dst, buffer + offset, segment_size);
+ if (mmc_send_cmd(mmc, &cmd, &data))
+ return 0;
- dst += segment_size;
- src += segment_size;
- size -= segment_size;
+ if (blkcnt > 1) {
+ cmd.cmdidx = MMC_CMD_STOP_TRANSMISSION;
+ cmd.cmdarg = 0;
+ cmd.resp_type = MMC_RSP_R1b;
+ cmd.flags = 0;
+ if (mmc_send_cmd(mmc, &cmd, NULL)) {
+ printf("mmc fail to send stop cmd\n");
+ return 0;
+ }
}
-free_buffer:
- free(buffer);
-
- return err;
+ return blkcnt;
}
static ulong mmc_bread(int dev_num, ulong start, lbaint_t blkcnt, void *dst)
{
- int err;
- int i;
- struct mmc *mmc = find_mmc_device(dev_num);
+ lbaint_t cur, blocks_todo = blkcnt;
+
+ if (blkcnt == 0)
+ return 0;
+ struct mmc *mmc = find_mmc_device(dev_num);
if (!mmc)
return 0;
if ((start + blkcnt) > mmc->block_dev.lba) {
- printf("MMC: block number 0x%lx exceeds max(0x%lx)",
+ printf("MMC: block number 0x%lx exceeds max(0x%lx)\n",
start + blkcnt, mmc->block_dev.lba);
return 0;
}
- /* We always do full block reads from the card */
- err = mmc_set_blocklen(mmc, mmc->read_bl_len);
- if (err) {
+ if (mmc_set_blocklen(mmc, mmc->read_bl_len))
return 0;
- }
- for (i = start; i < start + blkcnt; i++, dst += mmc->read_bl_len) {
- err = mmc_read_block(mmc, dst, i);
-
- if (err) {
- printf("block read failed: %d\n", err);
- return i - start;
- }
- }
+ do {
+ /*
+ * The 65535 constraint comes from some hardware has
+ * only 16 bit width block number counter
+ */
+ cur = (blocks_todo > 65535) ? 65535 : blocks_todo;
+ if(mmc_read_blocks(mmc, dst, start, cur) != cur)
+ return 0;
+ blocks_todo -= cur;
+ start += cur;
+ dst += cur * mmc->read_bl_len;
+ } while (blocks_todo > 0);
return blkcnt;
}